The presently disclosed subject matter relates to a bio-information analysis device for calculating a similarity degree (hereinafter, referred to as a matching rate) between two biometric waveforms.
When an arrhythmia, such as a premature ventricular contraction, is occurred, a treatment of selectively cauterizing an abnormal excitement site corresponding to a cause thereof is known. For this purpose, it is important to exactly identify an occurrence origin of the arrhythmia.
For example, a method of specifying an arrhythmia inducing lesion by recognizing a correlation of a signal waveform of a ventricular tachycardia occurred in a body of a subject and a pace-mapped signal waveform is disclosed from JP5160245.
In the method of specifying according to JP5160245, the legion is specified using a correlation coefficient of biometric waveforms to be compared. However, if shapes in comparison of biometric waveforms are similar to each other, the correlation coefficient exhibits a high value even when magnitudes thereof are different from each other. In this case, a matching rate having a high reliability cannot be obtained and thus an exact occurrence origin of the legion cannot be identified.
Accordingly, the presently disclosed subject matter provides a bio-information analysis device, which can increase reliability of a matching rate of biometric waveforms.
(1) According to an aspect of the presently disclosed subject matter, a bio-information analysis device includes a measuring unit that measures biometric waveforms of a subject, and a calculating unit that calculates a matching rate of the biometric waveforms based on shapes and magnitudes of the biometric waveforms measured by the measuring unit.
According to this configuration (1), magnitudes of waveforms as well as shapes of waveforms can be used as indicators to calculate a matching rate of biometric waveforms, thereby increasing reliability of the matching rate.
(2) In the bio-information analysis device according to the configuration (1), the biometric waveforms may be electrocardiogram waveforms.
According to this configuration, a matching rate having a high reliability in comparison of electrocardiogram waveforms can be calculated.
(3) In the bio-information analysis device according to the configuration (2), the electrocardiogram waveforms, from which the matching rate is calculated, may include a first waveform measured when a premature ventricular contraction is occurred and a second waveform measured when a waveform similar to an arrhythmia is artificially occurred by pacing.
According to this configuration (3), an occurrence origin of a premature ventricular contraction can be exactly identified based on the calculated matching rate having a high reliability, thereby allowing an unnecessary cauterization (ablation) to be avoided and also a lesion to be surely cauterized.
(4) In the bio-information analysis device according to the configuration (3), when calculating the matching rate between the first waveform and the second waveform, the matching rate may be calculated in such a manner that a point, at which the highest matching rate is exhibited, of points on the second waveform is overlapped with a highest amplitude point of the first waveform.
According to this configuration (4), an optimal reference point for overlapping in the biometric waveforms can be obtained, and accordingly the matching rate having a higher reliability can be calculated and an occurrence origin of the premature ventricular contraction can be exactly identified.
(5) In the bio-information analysis device according to the configurations (3) or (4), when calculating the matching rate, a waveform component, which is generated upon pacing and corresponds to a stimulation potential, of the second waveform may be excluded.
According to this configuration (5), a waveform component due to a stimulation potential can be excluded from biometric waveforms measured accompanying with pacing, and accordingly the matching rate having a further higher reliability can be calculated and an occurrence origin of the premature ventricular contraction can be exactly identified.
(6) In the bio-information analysis device according to any one of the configurations (3) to (5), upon calculation of a matching rate with respect to magnitudes of the biometric waveforms, a magnitude of a portion, which has a phase reversed relative to that of the first waveform, of the second waveform, may be changed to zero.
According to this configuration (6), a correction in which a magnitude of a portion, which has a reversed phase, of the biometric waveforms is calculated as zero, is performed, and therefore the matching rate having a further higher reliability can be calculated and an occurrence origin of the premature ventricular contraction can be exactly identified.
According to the bio-information analysis device of the presently disclosed subject matter, reliability of a matching rate of biometric waveforms can be increased.